Longest backcountry trails in a tropical/jungle area?

Enlist in the U.S. Army.

Be all that you can be.

–B.G.–

There's always the Darian Gap of Panama if an adventure from which ones return isn't assured is ok. Tropical places tend to focus on resorts and beaches, especially in Latin America. So far only the Hawaiian 9-mile+ "Z-trail" seems to fit the bill. There's almost half as much hike to get at the start, and it could be extended by bus (maybe a stealth camp either direction). The campgrounds are controlled by the state of Hawaii and need to pay a local business to park a car (hence my whole stealth/bus plan). Take a few days at camp, then repeat out. Not sure if the northern island of NZ counts as tropical but heard the northern part of the Te Araroa is tough.

1) Taman Negara NP in Malaysia
2) The Ituri Forest near Beni, Congo (formerly Zaire)

http://en.wikipedia.org/wiki/MegaTransect a very tough trip.
There are trails in Costa Rica up some of the mountains; apparently if you approach from a less popular direction you can get isolated. You might read some of Redmond O'Hanlon's books. I wouldn't recommend doing long distance jungle hiking without local guides.